Hi Ladies, please help me decide what to do

My son is turning two and we decided to throw him a little party at an indoor trampoline park. My good friend does balloons but hasn’t officially opened a business yet. I told her I would like to support her and she is super excited to help me set up balloons for my son’s bday. Upon asking what the price would be, she said I should just give her whatever I want. I kept insisting but the response was the same. She shared some pics(pics below) asking me which one I like and I told her whichever is less expensive to do because I want the party to be a bit simple. So I am not sure which she went with but these are some examples of the ones she showed so it will likely be something like this. Anyways, she said the supplies cost $80 and I sent that to her. My question is, how much do you think I should pay her for her service? I’m not sure if she’s making just one or one for each table(3 tables) Please help! I’ve asked her so many times and she just keeps saying whatever I give. What would you give if it were you?